MUNICH — The American secretaries of state and defense on Saturday presented an emotional defense of the Obama administration’s engagement in international crises in the face of widespread European and Middle Eastern criticism that the United States was retreating from a leadership role.

Speaking here at the Munich Security Conference, the most important trans-Atlantic security gathering, Secretary of State John Kerry expressed some exasperation with the criticism, rejecting “this narrative which frankly has been pushed by some people who have an interest in trying to suggest that the U.S. is somehow on a different track.” He went through a litany of American involvement in places like Afghanistan, Libya and the Middle East, saying, “I can’t think of a place in the world where we’re retreating.”

But at the same time, Mr. Kerry did not mention the American “pivot to Asia” that has been the source of European concern for several years. Nor did he, at least in prepared remarks and a brief question-and-answer session, have much to say about the turmoil in Ukraine, which Washington is seen to have largely left in the hands of the European Union.

Mr. Kerry spoke of Ukraine’s importance, saying, “Nowhere is the fight for a democratic, European future more important today than in Ukraine,” and he offered general support for the aspirations of Ukrainians to choose their future, saying that “the United States and the E.U. stand with the people of Ukraine in that fight” against coercion.

Mr. Kerry and his top aides met separately on Saturday with the opposition figures Arseniy P. Yatsenyuk, Vitali Klitschko and Petro Poroshenko. European officials who also met with the Ukrainians said that Mr. Yatsenyuk, who had turned down an offer to become prime minister, said he might consider the job if he could be given real power. He is concerned that given the near bankruptcy of Ukraine, he would be blamed for the consequences.

The officials said that European and American officials were beginning to discuss a possible financial package for Ukraine, to give any new government time to pass the difficult legislation required to qualify for a large, delayed loan from the International Monetary Fund.

“These discussions are just at the beginning,” one European official said. As for President Viktor F. Yanukovych, “he’s still playing for time,” the official said. The president is focused on winning another term in 2015 and fears for his personal safety if he leaves office, the official said.

Later on Saturday, Mr. Klitschko was on a panel with Ukraine’s foreign minister, Leonid Kozhara, and both defended their stated positions, although with some drama as Mr. Klitschko passed around an album depicting what he said were police brutalities, and Mr. Kozhara urged the opposition to take responsibility for controlling extremists.

Mr. Kerry urged the Ukrainian government to release prisoners, protect democratic rights and “form a technical government that can address Ukraine’s economic problems and meet the European aspirations of its people.”

Earlier, Mr. Kerry repeated Washington’s admonitions to Russia not to interfere in Ukraine, which Moscow has been doing from the start of the crisis. American and European officials here, speaking privately, said they were concerned that after the completion of the Winter Olympics in Sochi, Russia, this month, President Vladimir V. Putin might feel freer to act more openly in Ukraine to restore order there — through the use of riot police officers working alongside the Ukrainians, for instance, possibly in Ukrainian uniforms.

“Russia and other countries should not view the European integration of their neighbors as a zero-sum game,” Mr. Kerry said. “The lesson of the last half-century is that we can accomplish much more when the United States, Russia and Europe work together.”

He also gave a passionate defense of his deep involvement in the search for Israeli-Palestinian peace, rejecting remarks by Israel’s defense minister, Moshe Yaalon, who characterized Mr. Kerry’s efforts as “an obsession.” The status quo will not hold, Mr. Kerry said. “We’re working hard, because the consequences of failure are inconceivable.”

“We all have a powerful, powerful interest in resolving this conflict,” Mr. Kerry said. “We think it can be a game changer for the region.”

Defense Secretary Chuck Hagel, sitting alongside Mr. Kerry, sought to reassure Europeans that the United States was not abandoning the Continent as it rebalanced its interests — diplomatic, military and economic — to Asia after more than a decade of conflict in Iraq and Afghanistan. But his words were careful.

With the United States “moving off a 13-year war footing, it is clear to us, as well as President Obama, that our future requires a renewed and enhanced era of partnership with our friends and allies, especially here in Europe,” Mr. Hagel said.

“Since the end of the Cold War, the United States has continuously adjusted its defense posture to new strategic realities around the world,” he said. “As our force structure draws down following the end of our longest war, there will be — there must be — adjustments in our posture to meet new challenges.”

He cited his recent visit to Poland, where land-based interceptors for a European missile-defense system are to be put in place by 2018. In addition, four American missile-defense warships will be based in Spain, for service in the Mediterranean Sea — the first is en route now, he said.

But the overall statistics tell a troubling story to Europeans who believe America’s commitment can be measured, at least in part, by numbers. American military forces in Europe are down 70 percent since the end of the Cold War, and the Defense Department has closed almost 80 percent of its installations on the Continent in the same time period, according to American military officials.

Mr. Hagel also offered a clear-eyed, if grudging, acceptance of limits imposed by shrinking military budgets across NATO nations. Unlike Robert M. Gates, the former defense secretary who lectured NATO nations to spend more or risk undermining the alliance, Mr. Hagel said the challenge now was to spend more wisely on national security at a time when allied militaries would be getting less money. “Gates may have said it a bit differently,” Mr. Hagel said, but he added that he had similar concerns about a renewed commitment to shared responsibility.

“In the face of budget constraints here on the Continent, as well as in the U.S., we must all invest more strategically to protect military capability and readiness,” he said. “The question is not just how much we spend, but how we spend — together. It’s not just burdens we share, but opportunities, as well.”

A version of this article appears in print on , on Page A12 of the New York edition with the headline: Kerry and Hagel Defend U.S. Engagement Abroad in Face of Criticism. Order Reprints | Today’s Paper | Subscribe